1. MENSTRUAL CYCLES. Some female ultrarunners contend that they race better during their menstrual cycles. Could this be possible? Wouldn’t the loss of blood also account for loss of oxygen-carrying capacity?

Syb Gerrer
San Diego, Calif.

AT THE end of the menstrual cycle, the hormone testosterone is at the highest level in the cycle. Testosterone is a male hormone that helps strengthen muscles and is credited for aggressive behavior in males. The higher testosterone level could provide a female athlete with extra strength and competitiveness—two powerful components of great endurance racing.

The actual amount of blood lost during the menstrual cycle is miniscule, and the blood that is lost has been accumulating in the uterus during the menstrual cycle and is not part of the circulatory system that carries oxygen demanded for aerobic exercise. So, menstrual flow does not reduce a female ultrarunner’s oxygen-carrying capacity, that is, unless she’s running over the 12,600-foot Hope Pass in the Leadville Trail 100!

—Theresa Daus-Weber
is a winner of the famed Leadville Trail 100 and was a four-time member of the U.S. 100K team and has a 100K PR of 8:22.

I FOUND that immediately following my menstrual cycle I had my best performances. During my period, I always felt a bit sluggish, crampy, and overweight due to PMS weight gain. While individual differences matter, all the women I spoke with about this question said that they feel much better at the very end of their cycle and even seem to have a burst of energy.

—Gayle Barron
won the 1978 Boston Marathon and is a Team In Training coach living and working in Atlanta.

I LOOKED up the effect of menstruation on performance in Women in Exercise (2nd edition, 1994) by Mona Shangold, MD, and Gabe Mirkin, MD. They note that there is no consistent effect, suggesting that menstruation does not impair or enhance endurance.

Here’s my own opinion based on my personal experience. I ran several marathons while menstruating, and I found that I had a tougher mental outlook, of racing “in spite of my period.” This psychological approach seemed to help my performance, as I ran some of my faster marathons (including my PR) during my period. I think most women would say that they